ML24026A110
| ML24026A110 | |
| Person / Time | |
|---|---|
| Issue date: | 01/24/2024 |
| From: | David Rudland NRC/NRR/DNRL/NPHP |
| To: | |
| References | |
| Download: ML24026A110 (1) | |
Text
Recent International Operational Experience & Regulatory Actions David L. Rudland Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission NDE Technical Information Exchange Meeting January 23-25, 2024
Carbon Macro Segregation - Issue 2
Ingot Directional Conventional Forging Final Part Pouring of an Ingot ASME Carbon ~0.25%
Local measured ~0.25%-0.35%
Shift in RTNDT
Carbon Macro Segregation - Timeline 3
2015 EDF found irregularities when testing Flamanville head December 2016 ASN/MDEP found irregularities in Creusot Forge Audit - possible falsification of document 2016 AREVA notified ASN of over 400 parts manufactured since 1965
- some were sent to US 2016 NRC conducts preliminary safety assessment April 2017 NRC investigates allegation of records falsification 2017 ASN orders EDF to review all Creusot Forge documentation Jan 2017 All forgings produced by Creusot Forge for U.S. plants identified - 17 units identified Jan 2017 2.206 petition filed by Beyond Nuclear May 2017 NRC conducts a vendor inspection of Areva Creusot Forge June 2017 ASN/IRSN releases report a fast fracture analysis of CMAC June 2017 EPRI evaluation of the risk posed by CMAC in large nuclear forging issued Feb 2018 NRC staff final assessment released
Carbon Macro Segregation - NRC Response
- International bi-lateral discussions
- Addressing records anomaly through audit and review
- Addressing potential Part 21 and 10 CFR 2.206
- Addressing Management, Commission and Congressional concerns
- Developing preliminary and final safety assessment through use of LIC-504
- Safety impact was negligible (ML18017A441)
- Regional support 4
CRDM Thermal Sleeve Wear - Issue 5
CRDM Thermal Sleeve - Timeline 6
July 2018 Westinghouse issues NSAL18-1 Rev. 0 August 2018 NRC releases IN 18-10 and LIC-504 analysis recommending a smart sample August 2018 NEI releases NEI-03-08 Needed guidance November 2018 NRC releases Smart sample plan January 2019 NRC releases report on Smart sample Dec 2017 - Stuck Control Rod -
Belleville-sur-Loire 2 Feb 2018 - EDF declared to the ASN a significant safety event.
April 2018 - Letter MRP 2018-10 Notification of CRDM thermal sleeve wear May 2018 Wolf Creek finds 9 locations of lowered sleeve May 2018 Westinghouse submits notification of potential defect Part 21 May 2018 ASN reports another plant experiences a stuck rod
CRDM Thermal Sleeve - NRC Response 7
- International bi-lateral discussions at first indication of OE
- Addressing Management, and Commission concerns
- Developing preliminary and final safety assessment through use of LIC-504 (ML18249A081)
- Regional support and coordination through smart sample
- Smart sample data analyses and report generation (ML19035A503)
Framatome PWHT-Issue 8
After welding, local post weld heat treatment was performed using ceramic heaters Per a change in French regulation, Framatome conducted analyses during a program to optimize the process and found PWHT temperature not maintained over whole area - verified by Mock-ups Issue was with the serpentine heaters Part 21 was opened and impacted components identified including several replacement US components Issue resulted in PWHT at temps <50C from ASME limit but soak times were sufficient 7 US plants were supplied with components with this issue
Framatome PWHT-Timeline 9
September 2019, Framatome identified a deviation in the PWHT of certain components manufactured after 2008 October 2019 Framatome analyses suggest issue not reportable via Part 21 January 2020, Framatome identified another deviation in the PWHT process May 2020 Framatome reports analyses suggest issue not reportable via Part 21 Jan 2021 Framatome reports to NRC that a third issue pertaining to ID welds was discovered March 2021 Framatome reports third issue is not reportable
Framatome PWHT-NRC Response 10
- International bi-lateral discussions
- Reviewing Part 21 analyses meeting with Framatome
- Determination of immediate safety assessment - qualitative
- Regional support including end of cycle meeting support
French SCC-Issue 11 Most flaws found were very shallow and long Expanded inspection found over 100 flaws some up to 85% deep Root cause was attribute to thermal stratification and welding stress Safety injection system
French SCC-Timeline 12 Oct 2021 Flaws found at Civaux 1 Nov 2021 more flaws found at Civaux 2 and Penly 1 Jan 2022 flaw removed from Civaux were IGSCC March 2022 ASN expanded inspection to all ECCS/RHR systems March 2022 EPRI/PWROG kicked off Focus group March 2023, 85%
deep flaw found at Penly 1 - near hot leg March 2023 NRC conducts qualitative BeRiskSMART analysis April 2023 PWROG publishes PWROG-23007-NP, Revision 0 July 2023 NRC begins LIC-503 effort September 2023 NRC finalizes LIC-504 April 2024 PWROG publishes applicability report
French SCC-Response 13
- International bi-lateral discussions with France, Japan, Spain, UK
- Participated in Western European Nuclear Regulators Association (WERNA) to develop report and recommendation
- Addressing Management, and Commission concerns
- Determination of immediate safety assessment - qualitative (BeRiskSMART) and quantitative (LIC-504 ML23236A052)
- Regional support
- Several public meetings including Feb 21, 2024
THANK YOU 14